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In single Live game, 0-1, ratings W -156, B +10: How possible?

  • #1



    How is it possible to lose 156 rating points in one game, from 1672 to 1516, esp when playing someone less than 100 rating points below (Live Chess)? Plus, the opponent did not gain anywhere near that many rating points. BlackElo starts at 1590, goes up to 1600. (In the PGN & c. Wh starts at 1672, is reduced in one game to 1516--see below).


    "Your new standard rating is 1516 (-156).
    Match Scores: aisling42 (1516) [0.0] vs MASdeVera (1600) [1.0]"

  • #2

    If player A (1200) has played 0 game, and plays against player B, (1200), who's played 10000 games, obviously if player A wins, he/she will gain hundreds of points (as you probably experienced when you first went on this site) and player B's rating will change a bit.

    This makes sense if you consider probability intuitively, and the fact that player A is essentially unrated, and player B's rating is super established. 

  • #3

    Thank you Cherub_Enjel, but the numbers disagree.


    The player who gained 10 points (while I lost 156) has far more games, has a far more established rating, than I: they have 800+ games, I nave fewer than 60 (Live. Or Online). If Online/daily is being pulled into this, Online and Live/Rapid should not be mixed, esp since one of the two players has no Online games. Even there, recently losing in Online with a rating ~ 2200 to a rating nominally 1600 cost fewer than 60 points. The other player joined months before I did, years ago. My RD is ~ 100; I forgot to look for that of the other player.


    So, thanks, but I have to ask again: how is the foregoing possible? Maybe I am misunderstanding the reply.

  • #4

    Yeah, so the player whose rating is more established will have *less change* - because the rating is assumed to already by very accurate.

    Someone who is less established (you) will have more rating change. 


    I'm not sure if it's 10 and 156, but it would certainly be more for you than for your opponent, change-wise. 

  • #5

    This is how the Glicko rating system works.  If you've played a lot of games recently, your rating is assumed to be fairly accurate, and so you get smaller adjustments.  If you haven't played many games recently, your rating is assumed to be more of a provisional rating with a great deal of imprecision, so you get a large adjustment to try to reach a roughly accurate rating as quickly as possible.


    Not only that, but if you're playing against someone who has an established rating, it's assumes their rating is pretty accurate, so you'll get a somewhat larger adjustment.  If you're playing against someone who only has a few recent games, their rating is not considered to be a reliable guide to their true strength, so you don't get a very big adjustment.


    In the case of a new player playing someone with an established rating, both effects are in play.  That means the new player gets an enormous adjustment, and the player with the established rating gets a very small adjustment.


    Here's a link with more information on how the Glicko rating system works: https://en.wikipedia.org/wiki/Glicko_rating_system.  It's a variant of the better-known Elo system.


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